APPLICANT'S ABSTRACT: The need for valid treatment matching is one of the greatest challenges facing drug abuse treatment services today. This study will test a widely published treatment matching protocol in order to determine which, if any, of its criteria are valid and applicable to a publicly funded treatment population. The study proposed here is a prospective, randomized design in which the outcomes of treatment assignments which conform to a treatment matching protocol (match) are compared with medically and ethically permissible alternate assignments (non-match) which deviate from the protocol (but are nevertheless standard treatments often utilized in the community). The protocols to be tested are the Patient Placement Criteria of the American Society of Addiction Medicine (ASAM). The match vs. non-match comparison will be studied in two types of treatment settings: inpatient rehabilitation vs. day treatment, both of which provide detoxification as needed. Unlike a study which only compares higher intensity treatment vs. lower intensity treatment, the proposed design will randomize volunteer subjects into four cells of equal size: ( 1 ) matched to inpatient rehabilitation and assigned to inpatient rehabilitation, (2) non-matched (according to the ASAM Criteria), but assigned to inpatient rehabilitation, (3) matched and assigned to day treatment, and (4) nonmatched, but assigned to day treatment. The applicants represent a collaborative system which includes a state Bureau of Substance Abuse Services, a Target Cities central intake and provider network, academic medical centers and a state Medicaid managed care entity. This system offers a unique opportunity to study matching criteria because it is willing to provide the necessary range of treatment facilities and the funding infrastructure to pay for treatments for both the Medicaid and uninsured populations. The sample will be balanced for gender and race/ethnicity. The principal outcome measures will be: drug use severity (including relapse, frequency of drug use, treatment retention and corroborating serial toxicology), functional general health status and health service utilization costs. A 2x2 factorial ANOVA will be used to test the hypotheses that outcomes are determined by either treatment intensity, or ASAM Criteria match, or an interaction between treatment and match. The specific aims of the study are to: A. Test the predictive validity of the ASAM-Patient Placement Criteria B. Determine whether interactions occur between the Criteria & gender and race/ethnicity C. Propose revisions of any Criteria components which fail to demonstrate validity based upon empirical research